Fissures or cracks on the heel (or other areas of the foot) occur as a result of callused skin (hyperkeratosis), which is not flexible or elastic and cracks under pressure. They are divided into small and large, superficial and deep, and can also be bleeding or purulent. They represent a wound on the foot, which can lead to infection if not properly repaired and cared for. Fissures are cleaned and the hard skin is removed. The area is afterwards cared for or protected until the fissures heal.

Fissures are most often encountered by people who have a problem with excessive skin aging, dry skin, medical conditions (diabetes, psoriasis, etc.) and people with increased body weight. Problems arise especially in the summer, when the feet are, due to open footwear, exposed to dry and hot air and the ground surface.